Ok so maybe not the ultra-best, get free stuff kind of deal, but one I'm most pleased with: the Vancouver Art Gallery Family Membership. For $80 you get a year long membership for mom & dad (or you know, dad and his girlfriend) and two kids (in our case one 9 year old girl). And sure $80 isn't pocket change, but admission for a family of our size would normally cost $40 for one go, and as a family with one of us having the attention span of a 9 year old, you aren't really going to get hours upon hours of gallery viewing in. You're looking at about an hour of solid happy gallery time before things become a chore. With the membership, you don't feel guilty going in for an hour and coming back next month when you have more steam. Plus there are those great Super Sunday's geared at kids. And, for those times when we don't have Martin's daughter we can go in and take as much time as we like. You also get passes to all the opening parties which can be fun.
We spent an hour or so at the gallery on Sunday to take in the Brian Jungen exhibit, which was clever and good and a great show for kid accessibility, being not exclusively about stodgy oil paintings etc. and instead crafted largely out of materials kids see everyday (soccerballs, running shoes, couches etc). I think her favorite was the bird house (with live finchs!).